Sam is a large, obese, strong and muscular sea star with dark pink skin with red dots across her body. She is roughly twice the size of Patrick. She has black hair which she wears in a side ponytail that is fastened with a light lime green scrunchie. Her outfit consists of a blue-violet top with flowers that are similar to Patrick's pants and are the same color of her hair scrunchie, as well as a matching skirt.
Sam has a very deep voice, similar to a caveman's. She often calls herself "Sister Sam." She can literally put on her mean face whenever she completely loses her temper by turning her head around. She becomes very aggressive and destructive and can end up destroying anything.
Sam is shown to be highly aggressive by her clarity. This can be true as she is easily angered by any person she does not recognize. However, she expresses a brotherly bond with her younger brother and defends him from SpongeBob when she mistook physical contact as aggression.
In addition to her supportive behavior, her level of intelligence is relatively lower than Patrick's as she speaks incomplete language and has no regard for other people. She talks in third person.
She was lost in a surf when she and Patrick were kids, but eventually returned and gave Patrick a visit at some point.
Role in episode
Sam comes to town to visit Patrick. She then gets very violent and aggressive, demolishing SpongeBob and Squidward's houses. Squidward angrily objects, but she gets angry at him. She steals stuff from Squidward's house until it is completely destroyed.
Sam mispronounces "brother" as "brubber" and "decorate" as "blecorate."
She could be a reference to the Incredible Hulk, due to her speaking in the third person, and her exceeding strength.
She has the same hair color as her mother.
In the episode "Something Smells," Patrick mentions how he doesn't have a sister, contrary to Sam's existence.
Though it just could be Patrick forgetting that.
"Yellow square touch brubber! Makes Sister Sam MAD!"
"If Big Nose no like sand, big nose move!"
"Those boys mean! They pick on Sister Sam!"
"You mean... blecorate?"
"Sister Sam rearrange now!"
"Yellow square make brubber's eyes water!"
"Meanies go home!"
"Meanies is mean."
"Patrick okay! Sister Sam feel bad. Sorry she hurt Patrick. She protect little brubber." She go now."